Sulfate in concrete
Fingertips Easily access helpful, in-depth information on all things concrete construction—right at your fingertips. Back to all fingertips Sulfate in
For sole traders, students and anyone interested in concrete.
Bleeding and segregation
Bleeding is a form of segregation where some of the water in the concrete tends to rise to the surface of the freshly placed material. This arises due to the inability of the solid components of the concrete to hold all of the mixing water when they settle downwards (water being the lightest of all the mix constituents). Bleeding of the water continues until the cement paste has stiffened enough to end the sedimentation process.
Stainless steel reinforcement
The standard for stainless steel reinforcing bars is BS 6744, Stainless steel bars for the reinforcement of and use in concrete –
High Alumina Cement
High Alumina Cement (HAC) differs from Portland cement, being composed calcium aluminates rather than calcium silicates. Its rapid strength development made HAC popular from 1950 to 1970. However, mineralogical ´
Heavyweight concrete
Heavyweight concrete uses heavy natural aggregates such as barites or magnetite or manufactured aggregates such as iron or lead shot. The main land-based application is for radiation shielding (medical or nuclear). Offshore, heavyweight concrete is used for ballasting for pipelines and similar structures. EN 206:2013 defines heavyweight concrete as having an oven dry density greater than 2600kg/m3.
Fibres for concrete
The properties of fibres for use in concrete are 
Macro synthetic fibres
Macro synthetic fibres, sometimes known as ‘structural’ synthetic fibres, are made from a blend of polymers and were originally developed to provide an alternative to steel fibres in some applications. Initially they were identified as a potential alternative to steel fibres in sprayed concrete, but increasing research and development showed that they had a role to play in the design and construction of ground-supported slabs and a wide range of other applications. It has been found that macro synthetic fibres may be used with a wide range of concrete strengths.
What is Metakaolin?
Metakaolin is a pozzolan, probably the most effective pozzolanic material for use in concrete. It is a product that is manufactured for use rather than a by-product and is formed when china clay, the mineral kaolin, is heated to a temperature between 600 and 800ºC. Its quality is controlled during manufacture, resulting in a much less variable material than industrial pozzolans that are by-products. First used in the 1960s for the construction of a number of large dams in Brazil, metakaolin was successfully incorporated into the concrete with the original intention of suppressing any damage due to alkali-silica reaction.
Recycled glass aggregate
The concrete industry places a heavy demand on primary aggregate sources